38 CHAPTERS ON EVOLUTION. 



scientific investigation is to correlate the objects of its research ; or in 

 other words, to effect a classification and arrangement of subjects 

 destined for investigation. When the child groups the objects by 

 which he is surrounded into animals, vegetables, and minerals, he is 

 unconsciously laying the foundations of a scientific system ; and, in 

 reality, the naturalist simply enlarges the conceptions of the child 

 when he shows that differences, as fundamental in their nature as 

 those the child learns to note, can be determined between the 

 varied tribes of animals and the equally diverse groups of plants. 



Prior to the time of Cuvier, naturalists concerned themselves 

 chiefly with the description of the different species of animals and 

 plants, and with the determination of the characters whereby one 

 species was distinguished from another. The writings of Linnaeus, 

 for example, are largely composed of such descriptions, and if we add 

 to such details, others dealing with the habits and distribution of 

 animals and plants, we shall have completed the enumeration of the 

 chief aims of naturalists in bygone days. The popular zoology and 

 botany of to-day, which do not concern themselves with matters 

 beyond form and the recognition of species or the description of 

 habits, reflect, in a very characteristic and exact fashion, the natural 

 history studies of the past. It should be remembered, however, that 

 the classic naturalists, amongst whom Aristotle stands out con- 

 spicuously, dived somewhat more deeply into the history of the 

 animal kingdom than their modern successors. But it may be fairly 

 assumed that the ordinary naturalist, prior to Cuvier's time, con- 

 cerned himself not so much with the structure or morphology of living 

 beings as with the description of their external forms, peculiarities, 

 habits, and habitations. 



With Cuvier, a new and higher era of natural history study 

 dawned. Linnaeus had mapped out the animal world into (i) 

 Mammalia, (2) Aves, or birds, (3) Amphibia (reptiles, frogs, &c.), 

 (4) Pisces, or fishes, (5) Insecta (insects, spiders, &c.), and (6) 

 Vermes, or worms this latter group being, like that of the Linnaean 

 " Insects," a most heterogeneous division, and including all known 

 and lower forms of animal life, from the "worms" themselves 

 downwards as far literally as the senses could reach. It has well 

 been remarked that such a classification as the foregoing possesses 

 a representative in the vocabulary of well-nigh every language. 

 In this view it might be maintained that a popular conception 

 of a unity of animals underlying their obvious diversity was early 

 formed in the human mind. This is undoubtedly true, since the 

 division of the animal world into beasts, birds, fishes, insects, and 

 worms is a step in the construction of animal " types,'" to one or 

 other of which any animal may be referred. But the system in 

 question exhibits, after all, but little advance on the classification of 



